Galactic populations of radio and gamma-ray pulsars in the polar cap model

Peter L. Gonthier, Michelle S. Ouellette, Joel Berrier, Shawn O'Brien, Alice K. Harding

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


We simulate the characteristics of the Galactic population of radio and γ-ray pulsars using Monte Carlo techniques. At birth, neutron stars are spatially distributed in the Galactic disk, with supernova-kick velocities, and randomly dispersed in age back to 109 yr. They are evolved in the Galactic gravitational potential to the present time. From a radio luminosity model, the radio flux is filtered through a selected set of radio-survey parameters. γ-ray luminosities are assigned using the features of recent polar cap acceleration models invoking space-charge-limited flow, and a pulsar death valley further attenuates the population of radio-loud pulsars. Assuming a simple emission geometry with aligned radio and γ-ray beams of 1 sr solid angle, our model predicts that EGRET should have seen seven radio-loud and one radio-quiet γ-ray pulsars. With much improved sensitivity, GLAST, on the other hand, is expected to observe 76 radio-loud and 74 radio-quiet γ-ray pulsars, of which seven would be identified as pulsed sources. We also explore the effect of magnetic field decay on the characteristics of the radio and γ-ray pulsar populations. Including magnetic field decay on a timescale of 5 Myr improves agreement with the radio pulsar population and increases the predicted number of GLAST-detected pulsars to 90 radio-loud and 101 radio-quiet (nine pulsed) γ-ray pulsars. The lower flux threshold allows GLAST to detect γ-ray pulsars at larger distances than those observed by the radio surveys used in this study.

Original languageEnglish (US)
Pages (from-to)482-499
Number of pages18
JournalAstrophysical Journal
Issue number1 I
StatePublished - Jan 20 2002
Externally publishedYes


  • Gamma rays: theory
  • Magnetic fields
  • Pulsars: general
  • Radiation mechanisms: nonthermal
  • Stars: neutron

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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